The invention relates to a die for a tool set for mechanical joining.
EP 0 779 843 B1 discloses a tool set for producing joints on plate-shaped parts, this tool set having a first top tool part with a punch and a second bottom tool part with a round die. The die has an anvil with an anvil body, on which an annular element with a head-side sliding surface and a base-side connection surface are provided. Individual die segments which surround the anvil and are in the shape of ring sections have recesses for concentric flanging of the said die segments to the annular element, this flanging allowing a longitudinally directed movement of the die segments, each die segment being supported in a displaceable manner on the head-side sliding surface under spring preloading, for which purpose an elastic device brings the die segments to bear against the side surface of the anvil.
A disadvantage in this case is that the die segments, on account of their unfavourable ratio of overall height to radial extent, are more likely to tilt than to slide radially and in the process can become skewed and jammed as a result. The support of the die segments on the anvil body decreases during the longitudinally directed outwards movement, since the die segments at least partly run out of the guide. In addition, the die base body must be undercut in the anvil region in order to secure the die segments against axial displacement. This results in an increased risk of fracture of the die base body. The service life of such a die is therefore short. Furthermore, the annular element on the anvil body requires an increased overall height, as a result of which the accessibility of the joints in shaft-like components is greatly restricted.
WO 01/36124 A2 discloses a tool set of the generic type for producing joints on plate-shaped parts, this tool set comprising a round die. Individual die segments which surround the anvil and are in the shape of ring sections are arranged so as to be displaceable outwards on a supporting surface against spring preloading. In this case, the radial displaceability of the die segments outwards is limited by a stop which encases the supporting surface and is formed by a die sleeve. Furthermore, the stop serves to limit an axial movement of the die segments during their displacement outwards, for which purpose this stop has projecting guides which engage in undercuts of the die segments. A disadvantage in this case is again that the die segments can become skewed relative to the projecting guides and can become jammed as a result.
Furthermore, DE 694 08 080 T2 discloses a tool set of the generic type for producing joints on plate-shaped parts, this tool set comprising a round die. The die has four die segments which are surrounded by a housing. The housing is provided with elongated holes, pins extending into the interior of the housing in each case between two elongated holes. These pins engage in grooves which are formed on the die segments. During an outwards movement of the die segments against spring preloading, edges of the die segments can be moved into the elongated holes of the die housing, the pins which engage in the die segments counteracting a rotary movement of the die segments.
A disadvantage here is that the die segments can become skewed relative to the longitudinal holes, since the displacement is effected against a stop, the die segments being guided solely by supported pins.
An object of the invention is therefore to provide a die for a tool set for mechanical joining which die has a long service life and is at the same time of compact construction.